This invention relates to package structure, and more particularly to improvements in laminate structures enhancing its use as a thermoformed element of blister package structure.
Drugs in tablet or capsule form have been packaged in thermoformed blister packaging of the so-called press-through-package type fabricated from moisture barrier materials. In addition to moisture protection, it is further desirable that a material exhibit clarity, stiffness, and good thermoforming properties. Laminate structure comprising laminae of polyvinyl chloride (PVC) and chloro-trifluoroethylene, sold under the trademark Aclar, has been found suitable for packaging of the aforementioned type but is inherently costly. Plain PVC as well as PVC/polyvinylidene chloride (PVDC) combinations have also been used in an effort to reduce cost, but have not provided as good a barrier as the above identified Aclar combination.
It is a general objective of this invention to provide an improved packaging material of the hereinabove described type that is both economical and approaches the protective properties of the PVC/Aclar laminate structure.